title: Evaluation of a noninstrumented disposable method for quantifying serum theophylline concentrations.
abstract: OBJECTIVE
  To compare the performance of a new point-of-care theophylline assay (AccuMeter) with that of a standard laboratory assay (TDx), and another point-of-care method (AccuLevel).
  
  
  METHODS
  Prospective evaluation of consecutive patients receiving theophylline.
  
  
  METHODS
  University-based, ambulatory, allergy-pulmonary clinic.
  
  
  METHODS
  Forty subjects receiving maintenance theophylline therapy for asthma.
  
  
  METHODS
  Theophylline concentrations obtained from AccuMeter, TDx, and AccuLevel were compared.
  
  
  RESULTS
  The error, or difference, between TDx and AccuMeter results in 40 subjects on maintenance theophylline described accuracy. Mean error, an estimate of bias, was 1.1 (95% CI 0.72-1.5), 0.67 (0.34-1.0), and 0.98 (0.79-1.2) microg/ml for AccuMeter capillary, serum, and heparinized blood samples. Square root of the mean squared error, an estimate of precision, was 1.6 (1.2-2.0), 1.22 (0.90-1.5), and 1.14 (0.96-1.3) microg/ml for AccuMeter capillary, serum, and heparinized samples. Difference between AccuMeter and AccuLevel ME, an estimate of relative bias, was 0.59 (0.04-1.1) microg/ml. The difference in mean squared errors, an estimate of relative precision, was 0.86 (-0.54-2.3) microg/ml.
  
  
  CONCLUSIONS
  AccuMeter demonstrated good precision and minimal bias compared with TDx and AccuLevel . Method of sample collection had no effect on its accuracy.
authors.affiliation: Division of Clinical and Administrative Pharmacy, College of Pharmacy, University of Iowa, Iowa City 52242-1112, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Asmus
authors.forename: G
authors.initials: G
authors.lastname: Milavetz
authors.forename: M E
authors.initials: ME
authors.lastname: Teresi
authors.forename: M M
authors.initials: MM
authors.lastname: Weinberger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018927:Anti-Asthmatic Agents / Q000097:blood* / Q000627:therapeutic use; D001249:Asthma / Q000097:blood / Q000188:drug therapy; D002648:Child; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013806:Theophylline / Q000097:blood* / Q000627:therapeutic use
chemical_list: D018927:Anti-Asthmatic Agents; D013806:Theophylline